1. Field of the Invention
The present invention relates generally to a thin film electroluminescent (TFEL) edge emitter structure, and more particularly, to a multi-layer structure and method of constructing the same for providing TFEL edge emitter modules.
2. Description of the Prior Art
Electroluminescence is a phenomena which occurs in certain materials from the passage of an electric current through the material. The electric current excites the electrons of the dopant in the light emitting material to higher energy levels. Emission of radiation thereafter occurs as the electrons emit or give up the excitation energy and fall back to lower energy levels. Such electrons can only have certain discrete energies. Therefore, the excitation energy is emitted or radiated at specific wavelengths depending on the particular material.
TFEL devices that employ the electroluminescence phenomena have been devised in the prior art. It is well known to utilize a TFEL device to provide an electronically controlled, high resolution light source. One arrangement which utilizes the TFEL device to provide the light source is a flat panel display system, such as disclosed in Asars et al U.S. Pat. No. 4,110,664 and Luo et al U.S. Pat. No. 4,006,383, assigned to the assignee of the present invention. In a TFEL flat panel display system, light emissions are produced substantially normal to a face of the device and so provide the light source at the device face. Another arrangement utilizing the TFEL device to provide the light source is a line array, or edge, emitter, such as disclosed in a Kun et al U.S. Pat. No. 4,535,341, also assigned to the assignee of the present invention. In a TFEL edge emitter system, light emissions are produced substantially normal to an edge of the TFEL device and so provide the light source at the device edge. Edge emissions by the TFEL edge emitter system are typically 30 to 40 times brighter than the face emissions by the TFEL flat panel display system under approximately the same excitation conditions.
From the above discussion, it can be appreciated that the TFEL edge emitter structure of the Kun et al patent potentially provides a high resolution light source promising orders of magnitude of improved performance over the TFEL flat panel face emitter structure in terms of light emission brightness. However, there is a need for improvements in the overall structure and technique of constructing TFEL edge emitter modules to enhance performance overall.